1. Field of the Invention
This invention generally relates to a roller bearing, and, in particular, to a cage and roller assembly in a roller bearing suitable for use at an end of a connecting rod in an internal combustion engine.
2. Description of the Prior Art
A roller bearing is well known and used in various machines. For example, a roller bearing is used with a connecting rod of a compact internal combustion engine, for example, of a motor bike, and such a roller bearing typically includes a cage and roller assembly since it is relatively compact in size in the radial direction and it has a relatively large load bearing capacity.
One prior art example of such a roller bearing is illustrated in the Japanese Utility Model Application, No. 51-33608 (Laid-open Pub. No. 52-124353), assigned to the assignee of this application. This prior art example is so structured to include an increased number of rollers as schematically shown in FIGS. 5 and 6 herein. As shown, this prior art roller bearing includes a cage 11 having a pair of side stays 12 and 13 and a plurality of main stays extending between the pair of side stays 12 and 13 as spaced apart from one another at a predetermined pitch in the circumferential direction. A plurality of windows 14 are defined each between two adjacent ones of the plurality of main stays and each of the windows 14 receives a roller R rotatably therein Each of the main stays has a pair of side projections 16 projecting into the respective windows 14 from opposite sides thereof and these side projections 16 serve to prevent the associated rollers R from slipping away radially outwardly In addition, a roller guide portion 17 is provided on both sides at each end of each of the windows 14, and a roller holding projection 18 is formed at the inner side of each of the pair of side stays 12 and 13 as projecting axially inwardly so as to prevent the associated roller R from falling off inwardly.
However, in the above-described prior art structure, difficulty is encountered in manufacture, in particular, in forming the roller holding projections 18 which project inwardly Because of this difficulty, the roller holding projections 18 cannot be manufactured at high accuracy and thus there exists unstability in holding the roller R in its associated window 14. In extreme cases, there is a chance that the roller R will slip away from the associated window 14. If the roller holding projections 18 were to be manufactured with high accuracy, then it would push up the cost significantly.
In order to obviate the disadvantages of the above-described prior art device, there has been proposed another cage and roller assembly as disclosed in the U.S. Pat. No. 4,797,015 issued to Hidano et al. on Jan. 10, 1989, and assigned to the assignee of this application. The device disclosed in this patent has some improvements; however, there still remains some difficulty in manufacture, and, thus, there still exists a needs to improve the structure of a cage and roller assembly for use in a roller bearing.